M-Audio MobilePre USB User Manual page 23

Optimize for Slower Systems: Only the Mac OS 9 version of the
Mobile Pre control panel has this checkbox. It should be left checked if
your computer's processor is of G3 or slower speed.
Using the MobilePre USB
Now that we've finished connecting speakers and setting levels, you're
probably interested in getting started. This chapter explains how to
connect microphones and speakers to the MobilePre USB, and will explain
some of the units typical applications.
MobilePre USB Inputs
There are 6 inputs on the MobilePre USB, which are broken up into
functional pairs for XLR, 1/4" Line Level and a Stereo 1/8". All of these
inputs are merged into the same corresponding input channels on the
MobilePre USB.Any or all of these inputs can be used at any time, however
only 2 channels of audio will be recognized by your audio application.Your
software will record anything that is plugged into any of the MobilePre
USB's inputs.
Microphone Inputs
The MobilePre USB has two microphone inputs, labeled Ch. 1 and Ch. 2.
These XLR inputs raise the gain of a microphone level signal to a line level
signal for recording. If your microphone does not have an XLR output, you
will need to purchase an adapter or impedance transformer or use the
Stereo Mic Input, explained below. You can control the level of the two
microphone inputs using the Channel 1 and Channel 2 gain controls on the
MobilePre USB's front panel.
The 1/8" stereo input connects to the same channels as the 2 XLR
microphone inputs. It is provided for use with stereo dynamic
microphones or self-powered stereo condenser microphones with 1/8"
stereo outputs. Do not confuse this jack with similar looking jacks found
on consumer sound cards, which accept only mono microphone signals
that require a bias voltage to the microphone.
Phantom Power
The MobilePre USB provides phantom power for condenser microphones.
This 48 volt phantom power source can be switched on or off using the
front panel switch. An LED indicator lights when phantom power is
switched on and sending power to both microphone inputs.
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